CVE-2026-111171: Web3.py 7.15.0 through 7.16.0 and 8.0.0b2 through 8.0.0 CCIP-Read SSRF Bypass

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-15 · updated 2026-10-16
Weakness: CWE-918

Description

Web3.py 7.15.0 through 7.16.0 and 8.0.0b2 through 8.0.0 contains a server-side request forgery vulnerability because _check_ip_blocked() does not unwrap IPv4-mapped IPv6 addresses in CCIP Read URL validation. Malicious contracts can return OffchainLookup URLs with IPv4-mapped IPv6 hosts or AAAA records, making clients with CCIP Read enabled send requests to loopback, private, or link-local services.

Affected products

ethereum web3.py: from 7.15.0 through 7.16.0; from 8.0.0b2 through 8.0.0

References

https://github.com/ethereum/web3.py
https://github.com/ethereum/web3.py/blob/c8c1ed0c9e77e1a8b74902e6a6825e0b00534b10/web3/utils/ccip_url_validation.py#L16-L57
https://github.com/ethereum/web3.py/pull/3875
https://github.com/ethereum/web3.py/security/advisories/GHSA-5hr4-253g-cpx2
https://www.vulncheck.com/advisories/web3-py-7.15.0-through-7.16.0-and-8.0-0b2-through-8.0.0-ccip-read-ssrf-bypass
https://github.com/ApeWorX/web3.py/security/advisories/GHSA-5hr4-253g-cpx2

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